hi megan. I've been through what you are going through and a really good sonographer with excellent equipment should be able to see one placenta/one sac. By looking at your u/s pic at the top, it looks like your twins are mono/di. (same gestational sac/separate amnios). your still early in the pregnancy so things may be discovered as you get further along, but it sounds like you know what you are prepared for and that you are aware of TTTS. I know how you feel about really wanting girl/boy twins. When I got pregnant with our twins, I really thought for sure I was going to have a girl and a boy. BOY/BOY was I surprised!! But seriously, thankfully, they are both here and born healthy. I did eventually go on to have girl/boy twins 4 years later, so don't totally rule it out, it may happen!!